Casting of pottery and other like articles



B. I. ALLEN AND R. Y. AMES. CASTING 0F POTTERY AND OTHER LIKE ARTICLES.

Patented Apr. 6, 1920.

4 SHEETS-SHEET I.

jizz/miam B. J. ALLEN AND R. Y. AMES. CASTING oF POTTERY AND OTHER LIKE ARTICLES.

APPLICATION FILED AUG. 14| I9IZ.

atented Apr. 6, 1920.

4 SHEETS-SHEEI 2.

IL I

I I I B. J. ALLEN AND R. Y. AMES. CASTING 0F POTTERY AND OTHER LIKE ARTICLES.

` APPLICATION FILED AUG. I4, 1917-' 1,336,180. Patented Apr. 6, 1920.

4 SHEETS-SHEET 3- l y jizz/612210245.

B. J. ALLEN AND R. Y. AMES.

CASTING 0F POTTERY AND OTHER LIKE ARTICLES. APPLICATION FILED AUG. 14. 19H.

1,336, 180. Patented Apr. 6, 1920.

4 SHEETS-SHEET 4.

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UNITE STATES PATENT OFFICE BERNARD JAMES ALLEN, OF BLYTHE BRIDGE, AND ROBE-ET YETTON AMES, 0F GIDEA PARK, ENGLAND.

CASTING OF POTTERY AND OTHER LIRE ARTICLES,

Specification of Letters Patent.

Patented Apr. 6, 1920.

-Application led August 14, 1917. Serial No. 186,127.

To all 'whom it may concern.'

Be it known that we, BERNARD JAMES ALLEN and ROBERT Yn'r'roN AMES, both subjects of the King of Great Britain, residing, respectively, at Llangladure, Blythe Bridge, Staffordshire, England, and 36 Broadway, Gidea Park, Essex, England, have invented new and useful Improvements in the Casting of Pottery and other like Articles, of which the following is a specilication.

This invention relates to the casting of articles from slip mixtures in plaster, porous pottery or similar absorbent molds, and it has for its object to increase the absorbing power of such molds, so as to obtain a quick deposition of normal thickness or a deposition considerably thicker than could be obtained on' molds as'now used and' also to venable clay or other mixtures which-cannot ditions to be cast.

To this end, according to the invention, we provide means whereby a difference of pressure is set up on the twosides of the mold so that the deposited material is held close against the mold and the water is caused to drain rapidly away from the slip.

In carrying out our invention we inclose the mold entirely or partially in a chamber or jacket arranged and adapted to provide a vacuum or partial vacuum on the outside face or outside and inside faces ot' the said mold, suitable apertures being provided in the latter to permit the introduction of the clay slip or other mixture. The vacuum or partial vacuum roduced in the said jacket or chamber facilitates the evaporation from the mold of the absorbed liquid and permits further absorption to take place. The material in contact with the face of the said mold is the last to dry and as the moisture from the internal surface is drawn through the material the contraction due tordrying is reduced to a minimum and cracking is almost eliminated.

Or, we may apply pressure to the clay slip or other mixture either in lieu of, or i-n adbe used satisfactorily under natural condition to, the vacuum above described.

By our invention we overcome the ditliculties of manufacturing, by the casting process, large thick articles, such as glasshouse (dog-house) pots, vretorts, crucibles,

and the like homogeneously and without joints. Covered pots and the like articles having parts which, when drying, would `trating the employment of fluid the difference of pressure or. the two sides'w of. the mold, and this condition can be maintained until .the deposited material is dry enough to be strong and self-supporting.

To enable the invention to be fully understood we will describe it by reference to the accompanying drawings, in which Figure 1 is a vertical section of a twowtpiece mold with an external vacuum cham- Fig. 2 is a section of the joint between the two parts of the mold, drawn to a larger scale.

Fig. 3 is a view similar to Fig. l, illustratmg a form of mold, having both an internally and externally applied vacuum.

Fig. 4 is a sectional View of a mold having al vacuum chamber cast integrally with it.

Fig. 5 is a view similar to Fig. 3 illuspressure on the clay slip or other mixture.

Fig. 6 is a similar view of a one side mold designed for the production of articles of graduated thickness.

Fig. 7 is a view similar to Fig. l show ing the application' of fluid pressure to the clay slip; and

Fig. 8 is a sectional elevation of apparatus wherein mechanical pressure is applied to the slip.

Referring first to the construction shown in Figs. 1 and 2, a, a, indicate the half molds, which are of plaster or other porous absorbent material, the joint vbetween the meeting surfaces of the said tw-o half molds being made by the rubber packing strip b, shown to a larger scale in Fig. 2. c is a metal reinforcement whichl is provided around the mold a, and d is the jacket which incloses the said reinforced mold, which is suspended within it, the said jacket (l providing a space d1, which is in communication with a suitable vacuum chamber, by means of the connections c.

The apparatus is used as follows, that is to say, a vacuum being generated in the space d1, the slip is poured into the mold` as shown at f, and is allowed to remain therein until the desired thickness of deposit g has been made upon the inside surface of the mold a. As will be understood, and as has been pointed out above, the vacuum which is formed in the space d1, surrounding the outside of the mold exerts a suction action, so as to cause the deposited material to remain in close contact with the plaster of the mold and also rapidl to drain away the water from the clay sip, whereby articles can be not only rapidly cast, but can be obtained of greater thickness than has hitherto been practically possible. iWhen the desired thickness of deposit is obtained the clay slip is run off from the center of the cast piece. The removal of the slip is facilitated by admitting air to the vacuum chamber d1, while the unnecessary material is being run out.

In applying the invention to the casting of plumbago crucibles or refractory fire- .,clay, open-top, glass-house pots and the like,

it is preferable to employ molds to give both the inside and outside shape of the article and consequently to apply the vacuum to both the inside and outside molds. Such a mold is illustrated in Fig. 3 and it comprises the outside mold a made in halves, as described with reference to Figs. 1 and 2, and strengthened by the reinforcement 0 and surrounded by the vacuum jacket d, and also the inside mold h which lis suspended within the outer mold a by means of the cover IZ, clamped to the top of the vacuum jacket (Z, a spacebeing left between the said inside and outside molds, which is to receive the slip for forming the article required, in this case, a glass-house pot. The slip f is supplied to the mold through the filling funnels j and the space within the inside mold h is inV communication by the pipe c with the vacuum chamber, so that there is thus provided a vacuum chamber both on the outside and inside surface of the mold.

Where the article is of uneven or graduated thickness, as in the case of the glasshouse pot here dealt with, means are advantageously provided for dealing with such uneven or graduated thickness and for this purpose we may saturate with water the part or parts of the mold where the least thickness is required, or we may supplement the absorbing power of the mold wherethe greatest thickness is required, say, by the application to those parts of perforated or porous vessels containing a substance, such as calcium chlorid, which can conveniently be mixed with asbestos or other suitable fire-proof material. Or, we may achieve the same result in the manner indicated in Fig. 3, by making the -mold thickest Where the thinnest clay parts are required and so designing the vacuum jacket that the maximum evacuation takes place where the greatest thickness of clay is wanted.

In the case of large gas retorts, furnace blocks and other articles where the maximum exhaustion of the vacuum chamber is such as indicated at Z, Fig. 3. Also the parts of the mold may be clamped together with metal bands fitted with tension screws. When these precautions are taken itis possible to make use of a mixture, too thick and heavy ':for use under natural conditions, and an open porous structure can be obtained, or alternatively, a mixture of material too plastic to cast under natural conditions may be employed.

Fig. 4 shows apparatus specially suitable for thel production of pottery, such as electric insulators and similar articles. In this case the vacuum jacket Z forms an integral part of the molds a. Both the vacuum chamber and mold are in potteryand'have the outside surface only glazed to prevent vair being sucked through the vacuum jacket.

In applying the invention to the production of small articles a partial'vacuum produced by a laboratory filter is sufiicient, whereas for large thick articles a mechanically driven vacuum pump of high power is necessary. With the latter arrangement it is preferable to exhaust the air from a vacuum cylinder and connect the vacuum chambers on 'the molds to the said cylinder with pipes having suitable stop and air admission valves.

In Figs. l to t above described the desired difference of pressure between the two sides of the mold is effected by the provision of a vacuum upon the outside surface or surfaces, but, as above stated, the same result can be obtained by the utilization of pressure vappliedto the clay slip or other mixture either alone or in combination with a vacuum as above described.

In Figs. 5 to 8 we have shown several forms of casting apparatus in which both a vacuum and pressure upon the clay slip or other material are made use of.

Fig. 5 shows a mold of the type above d escribed and illustrated in Fig. 3, and in which, in addition to the external vacuum, there is also provided pressure upon the clay slip, this pressure being obtained b means of compressed air or other gas.' he funnels from which the slip is supplied, instead of directly communicating with the apertures in the mold, are fitted to connections cl having valves or stop-cocks Z1 and in communication with the reservoirs or containers Z2 through which the slip passes directly into the mold. The fittings or connections Isl are also in communication below thevalves or stop-cocks Z1 with a source of supply of compressed air or other gas by means of the pipe connection m fitted with the common valve n.

With this construction, when the mold has been iilled with slip mixture the stopcocks Z1 are closed so as to prevent entrance of further slip into the reservoirs or containers Z2. Compressed air or other suitable gas is then admitted through the valve n on to the upper surface of the slip mixture and exerts pressure upon the said slip so as to force the water contained therein through the'walls of the outer and inner molds a and it, the tendency being for the slip at the narrowest part of the mold to be maintained soft, while that of the thickest part is cast solid, thereby facilitating the manufacture of a sound and homogeneous article.

In the arrangement illustrated in Fig. 6 a one-side mold a only is made use of so that the internal vacuum chamber in the inside mold h is dispensed with. Furthermore, the vacuum acket d is so disposed relatively to the mold that a deposit of graduated thickness is obtained, as illustrated. The mold is mounted on a tilting frame o for the purpose of convenience in emptying out the superiuous and residual slip when a suiiiciently thick deposit has been obtained. IThe mold shown in Fig. 7 is designed for the casting of articles of even thickness throughout, and is a one-side mold so that only the external vacuum jacket d-is made use of. In other respects this mold is similar to, and acts in the same way as, that illustrated in Fig. 6.

In the mold described with reference to Figs. 5, 6 and 7 the pressure upon the slip is obtained from a uid medium, such as air. As vabove stated, however, direct mechanical pressure may be made use of and a mold operating on this principle is shown in Fig.

8. In this case the slip reservoirs Z2, funnels v j and the air suppl connections m, n are dispensed with and t e slip is fed to the mold from the main supply pipe p from a pressure pump or storage tank and through the flexible pipe Q and tap Z1. The pressure is maintained until theliquid has been filtered from the slip in the mold. is a valve to allow the air to escape when the mold is being filled. A l

The great pressure on the absorbent mold when'usingpressure on the slip in combination with a vacuum around the mold has as a result that the mold itself must be considerably reinforced and supported evenly over its surface, and in cases where all the support necessary cannot be obtained-from the studs c1 carried by owing to the design of the article to be cast, we may employ pebbles or balls of a suitable size which are'lled yinto the space inclosed by the Vacuum jacket, and'thus give the 'required'strength Such an arrangement is shown at s, Fig. 3.

' Claims:

An apparatus for casting pottery and the like, comprising an absorbent mold including means for varying the thickness of the vacuum jacket c;

thickness of which varies in accordance with the varying thickness of the article to be produced, and a vacuum chamber arranged on one side of said mold and through which air and moisture are adapted to be drawn.

3. An apparatus for casting pottery and the like, comprising an absorbent mold including means for varying the thickness of the pottery cast, and vacuum chambers arranged on each side of the mold and through which air and moisture are adapted to be drawn.

4. An apparatus Jfor casting pottery and the like, comprising an absorbent mold, the thickness of which varies in accordance with the varying thickness of the article to be produced, a casing surrounding said mold and arranged at varying distances from the mold, and a vacuum chamber located between the moldand casing.

5. A method of molding substances such as clay or like material, consisting in introducing the said material suspended in a liquid into a porous absorbent mold, and simultaneously causing the solid matter of said mixture to be gradually deposited upon the mold and the fluid to be withdrawn from the mixture' by maintaining a vacuum on one side of the mold until the desired thickness of the deposited matter is obtained.

6. A process of casting pottery from clay or like material consisting in introducing the said material suspended in a liquid into a porous absorbent mold, and simultaneously causing the solid matter of said mixture to be gradually deposited on the mold and the liquid to be withdrawn from the mixture by maintaining pneumatic pressure on said mixture until the 'desired thickness of the deposited matter is obtained.

7. Approcess of casting pottery from clay or like\material consisting in introducing the said material vsuspended in a kliquid into a porous absorbent mold, and simultaneously causing the solid matter of said mixture to be gradually deposited on the mold and the liquid to be withdrawn from the mixture by maintaining pneumatic pressure on the mixture and simultaneously maintaining a vacuum on oneside of the mold until the desired thickness of deposited matter is obtained.

' BERNARD JAMES ALLEN.

ROQBERT YETTON XMES. 

